[FFmpeg-devel] [PATCH] avfilter/vf_removegrain: replace qsort with AV_QSORT

[Ganesh Ajjanagadde]

On Mon, Oct 26, 2015 at 5:50 AM, Michael Niedermayer
<michael at niedermayer.cc> wrote:
> On Sun, Oct 25, 2015 at 03:10:27PM -0400, Ganesh Ajjanagadde wrote:
>> filter_slice calls qsort, so qsort is in a performance critical
>> position. AV_QSORT is substantially faster due to the inlining of the
>> comparison callback. Thus, the increase in performance is worth the
>> increase in binary size.
>>
>> Sample benchmark (x86-64, Haswell, GNU/Linux),
>> filter-removegrain-mode-02 (from FATE)
>> new:
>>   24060 decicycles in qsort,       1 runs,      0 skips
>>   15690 decicycles in qsort,       2 runs,      0 skips
>>    9307 decicycles in qsort,       4 runs,      0 skips
>>    5572 decicycles in qsort,       8 runs,      0 skips
>>    3485 decicycles in qsort,      16 runs,      0 skips
>>    2517 decicycles in qsort,      32 runs,      0 skips
>>    1979 decicycles in qsort,      64 runs,      0 skips
>>    1911 decicycles in qsort,     128 runs,      0 skips
>>    1568 decicycles in qsort,     256 runs,      0 skips
>>    1596 decicycles in qsort,     512 runs,      0 skips
>>    1614 decicycles in qsort,    1024 runs,      0 skips
>>    1874 decicycles in qsort,    2046 runs,      2 skips
>>    2186 decicycles in qsort,    4094 runs,      2 skips
>>
>> old:
>>  246960 decicycles in qsort,       1 runs,      0 skips
>>  135765 decicycles in qsort,       2 runs,      0 skips
>>   70920 decicycles in qsort,       4 runs,      0 skips
>>   37710 decicycles in qsort,       8 runs,      0 skips
>>   20831 decicycles in qsort,      16 runs,      0 skips
>>   12225 decicycles in qsort,      32 runs,      0 skips
>>    8083 decicycles in qsort,      64 runs,      0 skips
>>    6270 decicycles in qsort,     128 runs,      0 skips
>>    5321 decicycles in qsort,     256 runs,      0 skips
>>    4860 decicycles in qsort,     512 runs,      0 skips
>>    4424 decicycles in qsort,    1024 runs,      0 skips
>>    4191 decicycles in qsort,    2046 runs,      2 skips
>>    4934 decicycles in qsort,    4094 runs,      2 skips
>>
>> Signed-off-by: Ganesh Ajjanagadde <gajjanagadde at gmail.com>
>> ---
>>  libavfilter/vf_removegrain.c | 7 ++++---
>>  1 file changed, 4 insertions(+), 3 deletions(-)
>
> LGTM
>
> thanks

pushed, thanks.

>
> [...]
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
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>
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